The present invention relates to sprinkler units, and pertains particularly to a rotary stream sprinkler unit.
In my prior U.S. Pat. No. 3,854,664, issued Dec. 17, 1974, and, entitled "Sprinkler Systems", I disclose a sprinkler unit which has a rotating head that directs a plurality of rotating streams over an area to be watered. In that prior device, the streams of water are formed in nozzles in the rotating head. The rotating head has inlets to the nozzle on one end which engages and cooperates with an orifice plate for acting as a valve for controlling communication of pressurized water to the nozzles.
My U.S. Pat. No. 4,471,908 issued Sept. 18, 1984 and entitled "Pattern Sprinkler Head" discloses a similar sprinkler unit having V-shaped nozzles in a cylindrical rotating head. The nozzle inlet openings cooperate with an orifice in an orifice plate to vary the nozzle openings to the source of pressurized water. This combination delivers streams of water of variable length and volume from the nozzles in the distributor head. The orifice opening in the plate defines the spray pattern to be produced by the streams issuing from the nozzles in the rotating head.
In a subsequent application co-pending herewith, a plurality of passages in the unit forms nozzles which controls the stream size and velocity delivered to an open channel distributing head. The streams from the nozzles are directed into a plurality of open channels on a rotating distributor head for forming and distributing the streams.
The rotating head in the above described units is driven by a turbine through a reduction drive gear assembly within the body of the sprinkler unit. Such construction is complex and expensive to manufacture.
Sprinkler heads have been known wherein the distributor head is self-propelling, or more particularly stream propelled. The sprinkler head is rotated either by streams of water flowing from jets or nozzles in the head or by blades on the head struck by a stream of water, causing it to rotate.
Among the problems of the prior art self-propelled device is that it is difficult to control the velocity of rotation of the head. The velocity of rotation of the head is affected by friction, stream pressure and velocity, and other factors which ultimately determine the reach or distance that the distributed water travels from the head. The higher the velocity of rotation of the head, the shorter the reach of the streams from the head will be.
Some attempts have been made in the past to control the velocity of rotation of the distributor head by some type of damping means. However, these attempts have been unsatisfactory.
Accordingly, it is desirable that an improved rotary stream sprinkler unit be available.